Filtration of wastewater flowing over a surface of land with vegetation and water is a an artificial wetland
a stabilization pond
a biodegradable treatment
an open aeration pond

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.

it's c (engineer's do their work with mechanical stuff not on any living being)